Signature morpho-electric,transcriptomic, and dendritic properties of human layer 5 neocortical pyramidal neurons

1. Download : Download high-res image (159KB)
2. Download : Download full-size image

     

Glycosylation reactions — present status future directions

A short review of the present status of glycosylation reactions is presented. The reactivity of both proven and newer glycosylation methods are briefly discussed. Emphasis is placed on the control of stereochemistry and regiochemistry. As well, the identification and avoidance of side reactions is covered. Polymer-supported synthesis of oligosaccharides is noted as a promising direction for eliminating some of the problems associated with purification. It is suggested that a better understanding of the mechanism of glycosylation reactions is necessary for future improvements to stereoselectivity and regioselectivity. A key advance would be methods for enhancing the reactivity of weakly nucleophilic hydroxyls.Abbreviations BF₃ OEt₂ boron trifluoride diethyl ether complex - TMSOTf trimethylsilyl trifluorometh-anesulfonate - NIS NBS N-iodosuccinimide andN-bromosuccinimide - TfOH trifluoromethanesulfonic acid or triflic acid - AgOTf CuOTf₂ silver triflate and copper(II)triflate - Tf₂O triflic anhydride - IDCP iodonium dicollidine perchlorate - TEP triethyl phosphite - HfCp₂Cl₂ hafnium dicyclopentadienyl dichloride - Ac acetyl - Bz benzoyl - Bn benzyl - Ph phenyl - Me methyl - Et ethyl - Bu₄NOTf tetrabutylammonium triflate - Ph₂IOTf diphenyliodinium triflate - PhSeNPhth N-(phenylseleno)phthalimide - Pent 4-pentenyl - TCI trichloroactemidyl - TBDPS t-butyl diphenylsilyl - DTBP 2,6-di-t-butylpyridine - Tr trityl or triphenylmethyl Dedicated to Professor J.J. Krepinsky on the occasion of his 60th birthday     

Dietary Restraint and Stress-Induced Snacking in Youth

Objective: To determine whether dietary restraint modifies stress-induced eating in youth. Research Methods and Procedures: Snacking was measured in boys (9.5 ± 0.3 years) and girls (9.0 ± 0.3 years), with and without dietary restraint, across a control day after reading children's magazines and/or coloring, and on a stress day after giving a videotaped speech, with order of conditions counterbalanced. Children were divided into four groups based on dietary restraint and changes in perceived stress: low-restraint/low-reactive (n = 9), low-restraint/high-reactive (n = 13), high-restraint/low-reactive (n = 10), and high-restraint/high-reactive (n = 8). Body composition was estimated by skinfolds. Results: Energy intake of snack foods was influenced differently by dietary restraint and stress reactivity in the stress and control conditions (p < 0.01). After being stressed, low-restraint/low-reactive children ate fewer snacks and high-restraint/high-reactive children ate more snacks compared with the control condition. After covarying for percentage of body fat, the interactions remained (p < 0.01). Girls ate less than boys (p < 0.001), but sex did not influence eating in control and stress conditions. Discussion: Dietary restraint occurs in children and may influence the effect of stress on eating. Interpersonal stress decreases snacking in low dietary restrained youth but increases snacking in high dietary restrained children, perhaps because of stress-induced disinhibition.     

Oxidative transformation of a tunichrome model compound provides new insight into the crosslinking and defense reaction of tunichromes

Tunichromes, small oligopeptides with dehydrodopa units isolated from the blood cells of ascidians, have been implicated in the defense reactions, metal binding, wound repair, or tunic formation. Their instability and high reactivity has severely hampered the assessment of their biological role. Experiments conducted with the model compound, 1,2-dehydro-N-acetyldopamine, indicated that the instability of tunichromes is due to this basic structure. Exposure of this catecholamine derivative to even mild alkaline condition such as pH 7.5 causes rapid nonenzymatic oxidation. High performance liquid chromatography and mass spectrometry studies confirmed the production of dimeric and other oligomeric products in the reaction mixture. The nonenzymatic reaction seemed to proceed through the intermediary formation of semiquinone free radical and superoxide anion. Ultraviolet and visible spectral studies associated with the oxidation of tunichromes isolated from Ascidia nigra by tyrosinase indicated the probable formation of oligomeric tunichrome products. Attempts to monitor the polymerization reaction by mass spectrometry ended in vain. Tunichrome also exhibited instability in mild alkaline conditions generating superoxide anions. Based on these studies, a possible role for oxidative transformation of tunichrome in defense reaction, tunic formation and wound healing is proposed.     

Zirconia-Cu(I) stabilized copper oxide mesoporous nano-catalyst: Synthesis and DNA reactivity of 1,2,4-oxadiazole-quinolinepeptidomimetics-based metal(II) complexes

Abstract

Contemporary research reveals an undemanding protocol for the catalytic synthesis of 1,2,4-oxadiazole-quinolinepeptide in the incidence of a cost-effective and reusable mesoporous ZrO₂-supported Cu₂O (Cu₂ZrO₃) catalyst. This paper depicts a unique system for peptide bond synthesis staying away from toxic solvents and reactants. The catalyst was reused for four cycles without noteworthy loss in the activity, and the catalyst was genuinely heterogeneous. The method followed a simple workup procedure, and no column chromatography was needed. Further, the synthesized 1,2,4-oxadiazole-quinolinepeptide ligand (L), and its complexes of type, [FeLCl₂] and [CuL]Cl₂ were synthesized and characterized by spectral and analytical techniques. An octahedral geometry has been projected for Fe(II) complexes, while the Cu(II) complex exhibits a square planar geometry. The binding properties of the complexes with CT-DNA were studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. The photo-induced cleavage studies revealed that the complexes possess photonuclease activity against pUC19 DNA under UV–visible irradiation.     

Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency

Background: Due to genetic similarities with humans, primates of the macaque genus such as the cynomolgus monkey are often chosen as models for toxicology studies of antibody therapies. IgE therapeutics in development depend upon engagement with the FcεRI and FcεRII receptors on immune effector cells for their function. Only limited knowledge of the primate IgE immune system is available to inform the choice of models for mechanistic and safety evaluations.

Methods: The recognition of human IgE by peripheral blood lymphocytes from cynomolgus monkey and man was compared. We used effector cells from each species in ex vivo affinity, dose-response, antibody-receptor dissociation and potency assays.

Results: We report cross-reactivity of human IgE Fc with cynomolgus monkey cells, and comparable binding kinetics to peripheral blood lymphocytes from both species. In competition and dissociation assays, however, human IgE dissociated faster from cynomolgus monkey compared with human effector cells. Differences in association and dissociation kinetics were reflected in effector cell potency assays of IgE-mediated target cell killing, with higher concentrations of human IgE needed to elicit effector response in the cynomolgus monkey system. Additionally, human IgE binding on immune effector cells yielded significantly different cytokine release profiles in each species.

Conclusion: These data suggest that human IgE binds with different characteristics to human and cynomolgus monkey IgE effector cells. This is likely to affect the potency of IgE effector functions in these two species, and so has relevance for the selection of biologically-relevant model systems when designing pre-clinical toxicology and functional studies.